1. Field of the Invention
The present invention relates to a multifunctional portable electronic device such as an IC card, which incorporates, e.g., a CPU, a data memory, a built-in battery, and the like, and is used in a stand-alone mode to provide an electronic calculator function, a time display function, and the like, and is inserted in a terminal in use.
2. Description of the Related Art
Conventional, multifunctional IC cards have been developed. An IC card of this type incorporates a CPU (control element), a data memory, and the like, has a keyboard, a display unit, and the like, and is solely used to provide an electronic calculator function, a time display function, or the like, or is inserted in a terminal in use. The CPU, the data memory, and the like are incorporated as an LSI chip.
In an IC card of this type, a program is developed according to specifications presented by a customer, and thereafter, programming, debugging, tests, and the like are performed. Then, the manufacture of a new LSI chip is started from design of a mask. In this case, basic functions are stored in a program memory comprising a mask ROM.
For this reason, every time specifications are changed or a new function is added, an LSI chip must be manufactured, resulting in high cost of the LSI chip, i.e., an IC card. In addition, a development period (mainly for a program) is undesirably prolonged.